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Weschler Tests

Weschler Tests. WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence. History. 1939: Weschler Bellvue 1950: WISC 1955: WAIS 1974: WISC-R 1981: WAIS – R 1997: WAIS-III 2002: WPPSI-III 2003: WISC IV.

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Weschler Tests

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  1. Weschler Tests WAIS: Adult Intelligence Scale WISC: Intelligence Scale for Children WPPSI: Preschool and Primary Scale of Intelligence

  2. History • 1939: Weschler Bellvue • 1950: WISC • 1955: WAIS • 1974: WISC-R • 1981: WAIS – R • 1997: WAIS-III • 2002: WPPSI-III • 2003: WISC IV

  3. Rationale for Weschler’s tests • More appropriate content for adults on the WAIS • Broader coverage the Stanford Binet • Separate scores for components of intelligence • Better norms

  4. Stratified Sampling in WAIS For an test to be used for all adults in the US, what variables should stratified on in the sampling?

  5. Variables used to select a stratified sample in WAIS • Age: 13 age groups, 16 to 89 • Sex: M, F • Race: White, non-white • Geographic region: 4 regions • Occupation: 6 occupational groups • Education • Residence: urban, rural

  6. Example using 1995 Census • Consideration of a combination of region, age, and sex

  7. Structure of WAIS • Scores on 19 scales in several content areas: Information, Block Design, Word Reasoning • Scores on traditional theoretical organization of Verbal IQ, Performance IQ, and Full Scale IQ • Scores on four Indices resulting from factor analysis of the 19 content scales

  8. Profile Analysis: pathologies show more scatter, e.g. schizo Low Middle High • Compre X • Arith X • Similarities X • Vocab X • Digit X • Block X • Coding X • Objec Assem X • Digit Symbol X

  9. Profile Analysis: Brain damage Low Middle High • Compre X • Arith X • Similarities X • Vocab X • Digit X • Block X • Coding X • Objec Assem X • Digit Symbol X

  10. Profile Analysis: Psychopathic character disorder Low Middle High • Compre X • Arith X • Similarities X • Vocab X • Digit X • Block X • Coding X • Objec Assem X • Digit Symbol X

  11. Group Tests of Cognitive Abilities • Can be administered to more than one person at a time • Historically called “paper and pencil” tests • Now can be administered electronically • On computer • On line, web-based systems (ISSUES!!)

  12. Advantages • Standardization • Examiner has no/small influence • Mass testing • Multiple choice format simplifies scoring • Scoring can be objective • Adaptive testing • Better norms

  13. Disadvantages • Examiner cannot make observations about each individual, e.g. is person ill • Restrictions on the response mode: just make on paper (?) • More difficult to have individuals take different questions • Difficult to measure certain attributes, e.g., sensori-motor functions • Not appropriate for certain individuals, e.g., inexperienced with these formats

  14. Scholastic Aptitude Tests • SAT • ACT • GRE • MCAT • LSAT

  15. Some Paper and Pencil Tests of “g” • Hidden Figures Test -Gottschaldt Figures • Matrices • Raven Progressive Matrices • Figural Patterns • Cattell Culture Fair Intelligence Test

  16. Wonderlic Personnel Test • A measure of general mental ability “g” • Short, timed, 12 minutes • Several forms: 11 languages, Braille, large • 50 items • Spiral omnibus format: gets more difficult, changing topics • Word comparisons, disarranged sentences, following directions, number comparisons, number series, story problems, spatial, logic

  17. Primary Mental Abilities • Thurstone, 1938 • Weschler • 7 to 9 cognitive abilities • Resulted from theory and research finding showing clusters of behaviors • Examples of abilities and test items

  18. Multiple Aptitude Test Batteries • A “battery” is a coordinated set of tests measuring several attributes • Several test of related abilities developed, normed, evaluated, and packaged by one publisher • Examples • Differential Aptitude Tests (DAT) • General Aptitude Test Battery (GATB) • Armed Services Vocational Aptitude Battery (ASVAB)

  19. Differential Aptitude Test (DAT) • Verbal Reasoning • Numerical Ability • Abstract Reasoning • Space Relations • Mechanical Reasoning • Clerical Speed and Accuracy • Language Usage • Spelling

  20. Psychometric Information on the DAT • Norms: national sampling, ½ male and female, Grades 8 to 12, workers • Reliability • Parallel forms: .68 to .86, percentile bands • Validity • Predictive of grades in math, science, social studies, English; Follow up study • Support material: brochures, profile forms, career planning using Career Planning Qst

  21. Seven-Year Follow-up Study with DAT • 1430 senior high school students examined with DAT, then followed for 7 years to learn what school level and what occupation

  22. Criterion: Education level attained 7 years later • Educ level • Advanced degree • College graduate • Some college • Specialty school • No further school

  23. Criterion: Education level attained

  24. Criterion:Occupation entered

  25. Other multiple aptitude batteries • General Aptitude Test Battery (GATB) • Used in US employment offices • Controversy over race norming; CRA of 1991 • Armed Forces Vocational Test Battery (ASVAB) • Used in military induction centers

  26. Guilford’s Structure of Intellect Model • “Search model” – has heuristic value • 120 facets of intelligence • 5 Operations: kinds of mental processes • 4 Contents:what you are thinking about • 6 Products: the form in which the information occurs

  27. Ex: Cognition of semantic… • Units: vocabulary, synonyms • Classes: verbal classifications • Relations: verbal analogies, order • Systems: arithmetic operations • Transformations: similarities • Implications: “Effects” test

  28. Creativity: Divergent Thinking about ….

  29. Other Tests of Specific Abilities • Emotional Intelligence • Gardner’s Multiple Intelligences

  30. Disabilities and Testing • Diagnosing disabilities • Accommodating disabled individuals in testing

  31. Definitions • Child experiencing delays, or has condition which will result in delay • Individuals With Disabilities Act (1997) • Adult with a physical or mental impairment that limits a major life activity • American With Disabilities Act (1990)

  32. Diagnosing disabilities • Must be done by a qualified examiner • Must be documented in some formal, proven way • Poor performance is not necessarily the result of a disability

  33. Assessing various types of disabilities • Physical • Vision: optical expert • Hearing: audiologist • Motor: special ed person, PT, med doc • Mental/cognitive • Mental retardation: “IQ” tests: WISC • Adaptive behavior: Vineland • Emotional: personality tests, behavioral observations

  34. Accommodations • Access • Services • Testing • Forms, mode of response, environment, aids, time allowed • Standards for Educ and Psych Tests • Ethical Principles of Psychologists

  35. Two Points of View • Tests are biased • Tests are not biased

  36. Psychometric Terms related to test bias • Adverse Impact • Mean difference in scores • Disproportionate selection rates • Bias in measurement = slope bias • Differential validity: difference in r • Bias in prediction = intercept bias • Unfair discrimination • Systematic under-prediction of success

  37. “Tests are biased” • Arguments that cognitive ability tests are BIASED and should NOT be used to assess minorities

  38. Tests are biased • African Americans score 10-15 points lower than whites; Hispanic/Latinos score 5 – 7 points lower than whites • 5 point difference remains after using controls • IQ tests have white, anglo-saxon, middle class content • Ethnic minorities score lower because of differences in motivation and exposure to tests

  39. Tests are biased, continued • Tests are differentially valid (slope bias) • Tests under-predict success for minorities (“intercept bias”) • Validation research has used poor criteria • Test results induce negative expectations • IQ is partially environmentally determined • Use alternatives

  40. Heritability • Heritability is the proportion of total variance in test scores due to genetic factors: h squared • Total test variance = variance due to genetics + variance due to environment • Estimates of heritability in cognitive ability: • Some testing texts: 30- 40% • General literature: 50 – 70% • Older ages: 80%

  41. Twins’ studies

  42. Tests are not biased • Arguments that cognitive ability tests are NOT biased and should be used to assess minorities

  43. Tests are not biased African Americans and Hispanis score lower on numerous tests of cognitive ability • Test score differences persist even after controls for SES and even with the use of culture free and culture fair cognitive tests • Culturally different individuals from other groups do as well as whites • White examiners do not treat minority examinees differently

  44. Tests are not biased • Differential validity (“slope bias”) occurs no more frequently than chance. Well developed tests are equally valid • Tests do not under-predict success for minorities; if any thing they over-predict success for minorities • Cognitive ability tests predict success in school, occupations, military, life

  45. Tests are not biased • Tests provide diagnosis and help identify special educ and enrichment • Tests serve to evaluate outcomes of program; part of solution • IQ is partially (largely) genetically determined • Alternative are more biased; tests are “color blind”

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